The National Fire Protection Association estimates about 93% of U.S. homes have at least one smoke detector.

But, consider these startling facts:

• Almost half of all home fires and three-fifths of fire deaths occur in homes with no detectors.

• Your chances of dying in a home fire are cut in half if you have a working smoke detector.

• There are more homes with smoke detectors that don't work, than homes without any detectors at all. These poorly maintained units create a false sense of security.

A smoke detector is basically just an electrical circuit that gets interrupted or at least disturbed by particles. The circuit runs through a chamber where there is a very small separation between two electrodes. The electricity "jumps" across this open space. The current goes around and around. Meanwhile the microchip monitors the flow of electricity. As long as the flow is constant it does nothing.

It has been said that where there is smoke there is fire. It is even more true that where there is fire there is smoke. A fire sends little particles into the air. When these particles reach the smoke detector, they go through the little chamber where the electrons are flying from one electrode to the other. The smoke particles interfere with this flow enough to alert the microchip. The microchip is programmed to send a signal to the alarm. The alarm sounds and either someone takes a frying pan off the stove and silences the alarm or everyone exits the house in an orderly fashion and waits for the fire department to handle the blaze.

Installation
Locate your smoke detector as suggested in the Manufacturer's instruction manual supplied with the unit, usually on the ceiling, or on the wall within 12 inches of the ceiling.  You should have at least 1 smoke detector per level in your home, situated close to sleeping areas.  If you sleep with your door closed it is also advised to install a smoke detector in that sleeping area.

Testing
Smoke Detectors are provided with test features to allow regular testing of the unit. Manufacturers also supply instructions as to how to test their unit properly.  You should test your smoke detectors at least once a month.

Maintenance
Replace your smoke detector batteries 2 times each year, a good reminder is to change the batteries each time you change your clocks for daylight savings.
Keep your smoke alarm clean! Dust and grime may be affecting its operation. If your smoke alarm is more than ten years old, it may be better to replace it.

Power Failure
Smoke Detectors can be purchased with a battery, or equivalent, which will keep the unit working during a temporary power failure.